That's a very crappy way of printing strings
You should also note that in the bootloader as I have told you before you are limited to 512 bytes in which you must load a second stage using the int 0x13 and read however many sectors you want to whatever location in the memory you want.
In the second stage you should prepare to enter protected mode: Enable the a20 line so that you can access the full 4GB in protected mode, setup atleast 3 GDT entries (Null, Code, Data), set the lower bit in cr0, then do a far jump to set CS. Once you're in protected mode you can either load an additional GDT (since the usefulness of your bootloader's GDT can be doubted for some reason) or use the one from before. Then you must handle request for Interrupts and distinguish which ones are exceptions and which are interrupts. This is done by setting up the IDT and handling ISRs. Once you have a *strong* exception handler (you can print registers). I'd work on polling port 0x60 every time you recieve IRQ6 (keybord) for the current character then using a scan code to convert it to ASCII. At this point you can either implement your own variant of "printf" and start implementing your library, or do what I did and setup a sort of driver manager to manage requests for notification of drivers.
Like so:
ServiceA(console) requests Keyboard Notification
ServiceB(someotherservice) requests Keyboard Notificiation
Keyboard IRQ Handler recieves interrupt:
Sends to all of the currently "registered" services for the Driver
Advantages of this: You don't have to have a lot of code in your IRQ handler, just something to dish out whatever needed.
Additionally having an app be able to request scancodes "on the go" using some sort of getkb(int num) to read each character and format it into a string then return when the number is met.
After this I'd implement a scheduler and maybe pre-emptive multitasking whichever then have some kernel level tasks working and swithing first before you move to User Level.
Anything after that is up to you:
Possibly some sort of VFS compatiblity layer? Maybe just run on to implementing something like NTFS or ext2?
